Aurora is known as the ancient Roman goddess of dawn, but the word is more commonly known for its use in the field of meteorology. From a meteorological standpoint, an aurora is what happens in a planet's upper atmosphere when particles from space collide with particles from the planet's atmosphere. The result is a light show that has been described as mesmerizing by those who enjoy viewing this natural wonder repeatedly.
The Science Behind an Aurora
An aurora occurs when particles such as protons and electrons collide with atoms or molecules in the upper atmosphere of a planet. This kind of collision, once it takes place, then moves in line with the planet's magnetic field. Many other planets experience this besides Earth because the main contributing factor is the density of a planet's atmosphere. Another factor is a planet's proximity to the source of the radial particles themselves, like for instance, the sun.
As the sun expels these particles, they push out into space until they reach an obstacle like Earth. Then, they spread around the planet, making contact at certain points, typically the highest latitudes of a planet. The colors that are produced depend on what type of “excited” particles the collision consists of.
The product of the collision, or “exciting” the atom, is photons, which in this case can be detected by colored light. Which colors are produced depends on the contents of the particles: oxygen or nitrogen for the most part. Oxygen, for example, produces colors like red and green, whereas nitrogen can be responsible for blue.
Best Places and Times to View the Aurora Borealis
The Earth's North Pole is better known for the viewing of the aurora, mainly because more people live there than in Antarctica . This is why the aurora is more commonly called, Aurora Borealis, (Borealis describing the northern winds or northern areas of Earth).
Though the aurora has been reported in the sky in places as far south as Mexico City, the best locations for viewing are in the northern latitudes, in places like Alaska and Scandinavia. The best times for spotting the aurora in the northern hemisphere seem to be during the winter months or when the area is at its darkest, often around midnight. Also equally important is a clear sky for easier viewing.
Aurora activity is more difficult to predict than that of the weather, though some companies still attempt it. So, with all of the depending factors involved, even those who travel north for the specific purpose of viewing aurora, are not guaranteed the pleasure of actually witnessing any activity of this nature.
Witness Accounts of Aurora Borealis
People travel north from all over the globe to witness this profound expression of nature. It has been described in many ways by the public using highly descriptive terms, such as luminous or glowing. Many also say that the colored sky patterns resemble curtains or even waves.
Images of the aurora seem to indicate that if one were to light up the currents of the ocean with some kind of luminescent particles, the images produced might be similar. This suggestion gives one the idea that magnetic fields aren't all that different from ocean currents, only that they contain different particles, and the levels at which they can be viewed differ entirely.
It is also known that this phenomena shouldn't technically be capable of carrying sound waves due to the upper atmosphere being so thin. Even still, there have been hundreds of accounts of people hearing hissing, or swooshing sounds when viewing the spectacle.
One thing remains certain in the case of the Aurora Borealis, the complex nature of its very existence will continue to intrigue people in times to come.
Sources:
“Frequently Asked Questions about Aurora and Answers.” University of Alaska Fairbanks.
Geophysical Institute. Last updated 12 May 2009. Accessed 19 Jan 2010.
Alexis Garrett - I consider myself an open minded individual with a massive excitement when it comes to learning about others without judgment or ridicule. ...
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